AWARD OF EXCELLENCE / BUILDINGS Redevelopment of Maple Leaf Gardens

Juror Comments:

“This is an outstanding example of the adaptive reuse of a heritage building where the requirement to fully preserve the historic brick facade and dome roof led to highly innovative engineering solutions. The engineers likened the challenge to
building a ship in a bottle — after first dismantling the ship that was already there!”

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Built in 1931 and declared a Heritage Building in 1991, Maple Leaf Gardens in downtown Toronto stood empty and unused for 12 years after the NHL team moved. But in a unique partnership, the iconic building was redeveloped into a Loblaw store and Ryerson’s Athletic Centre.

The redevelopment of this landmark was more than just a cosmetic renovation to an existing building. Constructing a multi-level parking, retail store and athletic centre is in itself not uncommon. But to construct these inside a heritage building with limited access for materials and equipment while preserving the historic brick façade and domed roof — this required detailed engineering and planning.

Loblaws required a store at ground level and a loading dock; Ryerson needed an arena with seating for 2,500 people, plus a gymnasium and training facilities. The Ryerson rink is on level 3, with a concourse level at the top of the seating bowl.

For much of the construction, the only access in and out was a new opening 18 ft. wide and 15 ft. high where a loading dock would eventually be constructed. Figuratively, constructing the new structure was similar to building a ship in a bottle. The exception, being that the bottle already contained a ship that had to be dismantled piece by piece without breaking the bottle.

Shoring the old,

inserting the new

Starting in January 2010, demolition, excavation and construction proceeded simultaneously. Construction drawings were issued on a floor by floor basis.

Temporary steel bracing was installed within the original concrete frames at the east and west sides of the building, and at the north and south ends large temporary box trusses, 10 ft. deep and 26 ft. wide spanning 202 ft., were installed between existing buttresses at the corners of the building.

At the corner buttresses, which support the entire weight of the domed roof, caisson walls were installed adjacent to footings to laterally support the soil under them, while the surrounding area was excavated down to the parking level.

With the new parking level 13 ft. below ground level at the south side and up to 21 ft. below ground level at the north side, significant portions of the exterior foundation walls required underpinning, using a combination of traditional underpinning and mini-piles.

The new construction within the building is a combination of cast-in-place concrete and structural steel, both flat slab and beam and slab systems. The slab below the rink is extremely critical because of the flatness requirements for the rink slab.

Structural steel framing was used in the long span areas. Because of the limited access into the building and the long reaches required for steel erection, much of the upper steel was erected early in the construction.

Throughout the demolition and construction, the existing structure and exterior walls were remotely monitored around the clock for any movement using an OSMOS system. Alarms were sounded and work stopped if movements exceeded a pre-determined safe threshold.

As the new interior structure was completed and connected to the original exterior, the temporary bracing and the last remnants of the original interior were removed. Final removal of construction equipment was through a temporary opening in the roof.

Revitalized and busy

With the opening of Loblaws in November 2011 and the Mattamy Athletic Centre (the official name of Ryerson’s Athletic Centre) in September 2012, the corner of Carlton and Church Streets is once again filled with excitement, and Canadians can once again experience the ambience and history of Maple Leaf Gardens. The redevelopment is the very definition of adapted reuse. Unlike other historic arenas in Boston, Detroit and Chicago that were completely demolished, the existing heritage structure was preserved and the Gardens live on.cce

Project name: Redevelopment

of Maple Leaf Gardens, Toronto

Award-winning firm / structural engineer: exp Services, Markham, Ont.

(Paul Sandford, P.Eng.; Weimin Liang, P.Eng.; Gordon Ho, P.Eng.; Anthony Di Stefano, P.Eng.; Andrew Kaminker, P.Eng.; Allan Parker, Eng.; Gary Moloney, P.Eng.; Godfrey Ng)

Owners: Loblaw Properties, Ryerson

University

Other key players: Loblaw – Turner

Fleischer Architects (architect), LKM SNC-Lavalin (mechanical), Hammerschlag & Joffe (electrical). Ryerson University –

BBB (architect), Genivar (project

management), TMP (mechanical),

Mulvey and Banani (electrical).

ERA (heritage architect); Aercoustics

Engineering (acoustics and vibration); Buttcon (general contractor).